ᐅ Use of Room Above Garage

After reading in several places that it is difficult to officially use the space above the garage, for example as an office or guest room, I wanted to present a different idea:

Is it possible to use the space if I maintain a distance of 3m (10 feet) from the neighbor and do not build the garage as a boundary wall?

What needs to be considered here?

You definitely need a building permit / planning permission for an extension on top of the garage. I don’t know which state or region you are from, as the requirements vary from place to place, so unfortunately I can’t provide more specific information.

I am from Bavaria.